Every batch of beer I have ever made has a harsh overly-yeasty, overly-bitter (even astringent) flavor. I would guess wild yeast contamination, but I am ridiculously anal about making sure everything is sterilized well and kept covered at all times.

Because of the harsh yeastiness, it occured to me that I may be leaving too much yeast in contact with my beer. Would it be beneficial to use a blow-off fermenter to get rid of some of that crap during fermentation?

If so, I have another question. With my plastic Brew Pail, there is ample room to seal the lid and then shake the hell out of it when I pitch my yeast. Since a blow-off fermenter requires a small amount of headspace, how do I ensure proper aeration during pitching? Keep in mind that I have no oxygen tanks or anything hardcore like that.

Another idea I had was to clamp a muslin bag over my siphon when moving to the secondary, but I’m afraid this might also block out some of the yeast still in suspension, and I won’t get a decent carbonation later. Has anyone tried this?

We'd need to know more about your recent batches (recipe and process) to help out.

"I would guess wild yeast contamination, but I am ridiculously anal about making sure everything is sterilized well and kept covered at all times."
It's rare that you would infect one brew if you're careful and virtually impossible to infect every one of your brews.

"Would it be beneficial to use a blow-off fermenter to get rid of some of that crap during fermentation? "
I've done a ton of brews (extract and AG's) and never once had a krausen (foam) leave the fermenter. It will either fall to the bottom after fermentation or you can siphon around it.

using a carboy..."how do I ensure proper aeration during pitching"
I always aerate in my bucket and then siphon into my carboy.

"Another idea I had was to clamp a muslin bag over my siphon when moving to the secondary, but I’m afraid this might also block out some of the yeast still in suspension, and I won’t get a decent carbonation later. Has anyone tried this?"

There is plenty of yeast in the liquid of your beer. If you can siphon just above the trub on the bottom and stop the siphoning when the clearer liquid is transferred, you'll still have plenty of yeast. If you want to filter out more stuff you can use this contraption. I still have plenty of yeast for continued fermentation in the secondary and carb conditioning.

Astringent taste is most often caused by boiling specialty grains that should instead be steeped at 150-160 degrees.

Too much yeast (to my pallette) tastes more like a slice of bread dough.

What made me think of using a blow-off hose was the following from NCJoHB: “This method of fermenting has the extra advantage of ‘blowing off’ excessively bitter hop resins, excess yeast, and other things…”

As far as what exactly the off-flavor is…well, I can’t quite identify it. There is an overly yeasty, bread-like taste. But there is also the astringency. In my last batch I wised up and didn’t boil my specialty grains, and that helped that aspect a lot, but it is still there a little bit.

But there is another note that I can only describe as harsh and artificial. And the key here is that it smells exactly the same as it tastes, so it isn’t just a flavor thing like bitter or sour. I would say chemical-like, but it doesn’t make me think of phenol or sulfer.

-Specialty grains and hops were added in a muslin bag.
-Everything sanitized in Star-San
-I couldn’t get the wort cooled down fast enough, so I left it overnight, and then pitched the yeast in the morning. It was sealed the whole time, though.

-I couldn’t get the wort cooled down fast enough, so I left it overnight, and then pitched the yeast in the morning. It was sealed the whole time, though.

OK, I take it back. I think it was wild yeast.

Wild yeast are pretty much everywhere, and every wort has some in it.

Ideally, the wort is quickly chilled and pitched with a huge amount of yeast cells. They begin reproducing and then actively fermenting very quickly, overwhelming the competition from the wild yeasts.

But when your wort sat overnight, it gave the wold yeasts a head start--they had time to reproduce and get to work before being overwhelemed by the on-purpose yeast.

Wild yeast is not so much a contamination issue (every batch has it), but a containment/competition issue. It's the main reason why quick chilling and pitching of adequate yeast cell counts is important.

I assumed that as long as I kept everything covered, it wouldn't be a problem. The only time I had my pot uncovered after boiling was when I added and removed the muslin bag to steep the aroma hops, and when I poured the wort into the bucket. Wouldn't bacteria have just as easy of a time floating into my open container? I know I don't have bacterial contamination. (That happened to my friend once and it tasted like lemon juice.)

Also, this is the only batch that has actually sat overnight. However, I will say that all of my other batches have taken a few hours to cool down. I definately need a bigger sink to put ice in or an immersion cooler.

Oh, one more thing....would a beer be drinkable after wild yeast contamination? This latest batch is definately drinkable, just kind of "funky" and not as good as what I could get from the store.

My question: What kind of water are you using? Water doesn't play as big of a role in extract, but if you have high chlorine or chlorophenols, sometimes even really hight sodium levels you can get some pretty funky flavors going on. I have to admit, I only skimmed the thread, but it didn't seem like anyone mentioned this.

So like everyone else you've got a few issues mixed together. It'll take some experimentation to get them all straighted out... here's my take,

1) Astrigency (tannins like young red wine, make you tounge dry and fuzzy) is caused by boiling grains. You said "I wised up and didn't boil my grains" on the last beer but by implication not the previous beers. So, don't boil your grains, I think you've got this covered.

2) Letting the wort sit overnight it WAAAY too long. Having an immersion chiller is best but takes $$. Taking a couple hours to cool it in an ice bath is acceptable and many, many brewers have good results doing this.
I suspect on this batch you got some sort of infection because of the sitting overnight. Did you get sour beer? you can get sour contaminations (lactobaccillis, or aceto-bactor) as well as the band-aid, stinky feet kind.

So, time to try a third. No boiling, no overnight sit. See what you get.

Finally, convential brew wisdom says that no toxic bateria can survive in beer. It may tast like hell but it won't hurt you.

If you have any more beer you can try mixing to cut down the taste. If it's actuallyl soured this is what the pros do to control sourness. Or cook with it.